Resources may be drawn from one or several queues so
that the properties of those drawn from one queue
match those drawn from the other queue(s). In the
worst case, matching fails. This situation typifies
matching problems. For example, a water boiler has a
designated location in a house under construction;
when the boiler is ready to be installed, workers must
have access to that designated location to work; no
other location will do. Another example is to install
only complete pipe runs (Howell and Ballard 1996) or
to load various structural steel shapes onto flatbed
trucks not to exceed the truck's dimensions or load
capacity (Martinez 1996).